A rapid rise and fall within 90 deg. was desired. This originally called for the pink cam contour but produced severe pressure angles. The condition was improved by providing an additional green cam which rotates 4 times faster than the pink cam.
The pink cam was then completely cut away for the 90 deg. The desired motion, expanded over 360 deg. (90x4=360), is now designed into the green cam. This results in the same pressure angle as would occur if the pink cam rise occurred over 360 instead of 90 deg.